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Java > Open Source Codes > nl > justobjects > pushlet > util > Servlets


1 // Copyright (c) 2000 Just Objects B.V. <just@justobjects.nl>
2 // Distributable under LGPL license. See terms of license at gnu.org.
3
4 package nl.justobjects.pushlet.util;
5
6 import javax.servlet.http.HttpServletRequest JavaDoc;
7 import javax.servlet.http.HttpServletResponse JavaDoc;
8
9
10 /**
11  * Servlet utilities.
12  *
13  * @version $Id: Servlets.java,v 1.1 2004/09/20 22:01:40 justb Exp $
14  * @author Just van den Broecke - Just Objects &copy;
15  */
16 public class Servlets {
17
18     /** Get parameter; if not set or empty return null. */
19     public static String JavaDoc getParameter(HttpServletRequest JavaDoc aRequest, String JavaDoc aName) {
20         return getParameter(aRequest, aName, null);
21     }
22
23     /** Get parameter; if not set or empty return specified default value. */
24     public static String JavaDoc getParameter(HttpServletRequest JavaDoc aRequest, String JavaDoc aName, String JavaDoc aDefault) {
25         String JavaDoc value = aRequest.getParameter(aName);
26         if (value == null || value.length() == 0) {
27             value = aDefault;
28         }
29         return value;
30     }
31
32     /** Set HTTP headers to prevent caching. */
33     public static void setNoCacheHeaders(HttpServletResponse JavaDoc aResponse) {
34         // Set to expire far in the past.
35 aResponse.setHeader("Expires", "Sat, 6 May 1995 12:00:00 GMT");
36
37         // Set standard HTTP/1.1 no-cache headers.
38 aResponse.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
39
40         // Set IE extended HTTP/1.1 no-cache headers (use addHeader).
41 aResponse.addHeader("Cache-Control", "post-check=0, pre-check=0");
42
43         // Set standard HTTP/1.0 no-cache header.
44 aResponse.setHeader("Pragma", "no-cache");
45
46     }
47
48 }
49
50 /*
51  * $Log: Servlets.java,v $
52  * Revision 1.1 2004/09/20 22:01:40 justb
53  * more changes for new protocol
54  *
55  *
56  */
57
58
59
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